The present disclosure is related to integrated circuit packaging, and more particularly to an integrated circuit package which includes a light source such as a light emitting diode or the like together with an integrated circuit which are encapsulated in an opaque encapsulation material such that when the light source emits light, at least some of that light may be seen on the surface of the opaque encapsulation material.
Associating a light source with a semiconductor device is known in the art. The light source may serve a purely functional role, such as in an optical fingerprint sensor, which uses the light source to illuminate a portion of a finger. In one example, the illuminated portion of the finger is then examined and a fingerprint pattern captured therefrom. See U.S. Pat. No. 7,440,597, incorporated herein by reference.
Light sources associated with semiconductor packages may also have other uses, such as providing a user with some sort of visual feedback during operation of a device. See, for example, www.validityinc.com/post.aspx?id=147. Another example is disclosed in U.S. Pat. No. 7,272,723, incorporated herein by reference, in which a light emitting diode (LED) provides a user with a visual indication of the operations being performed by a peripheral key management device. In one embodiment of such a device, the light source is in electrical communication with a substrate which has electrical connection to processing hardware. The light source and substrate are enclosed within the interior of a partially translucent or transparent housing. As is typical for such devices, the housing is a structure molded prior to introducing the substrate and LED. During assembly of the final device, the substrate and LED are secured within the pre-molded housing. In general, such devices are relatively large, and while electrically coupled to the substrate, the light source is not mounted on or an integral part thereof.
In general, there is great pressure on producers of integrated circuit-based device to provide ever-more compact devices with a lower cost of manufacture. Silicon-based sensors, such as capacitive fingerprint sensors, are one such example. These silicon fingerprint sensing devices are commonly found in laptop computers, in PC peripherals such as keyboards and mice, in some models of cell phones and personal digital assistance devices (PDAs) and so forth. The small amount of space available for these devices mandates as much integration of the components comprising the silicon fingerprint sensor as possible. And the supply chain model puts great pressure on device suppliers to lower costs.
Yet, there is also great pressure to innovate and introduce new features to provide product differentiation, ease of use, reliability and so on. One such feature in the area of silicon fingerprint sensors is an attractive device appearance. Another is a visual mechanism for providing a user with feedback on device status and operation, such as where and when to swipe or place a finger over a sensor, whether a swipe or finger placement was successful, and so forth.
To date, there has not been available an IC package design which provides an attractive appearance, visual user feedback, and other functionality of an illuminated integrated circuit package (again, of which a capacitive fingerprint sensor is one example), while also being of compact footprint, compatible with existing manufacturing techniques, materials, and tools, and which does not otherwise increase the cost of device manufacturing more than the cost of the light source itself. The present invention addresses these shortfalls.